In many subsea oil and gas well applications, flying leads and stab plates are employed to connect hydraulic hoses and electrical cables between subsea production equipment, such as subsea trees and manifolds. The connections are formed with the assistance of a remotely operated vehicle (ROV). The flying lead generally comprises a length of umbilical having copper conductors, optical fibers and/or hoses which can range in length from a few meters to 200 or more meters. The flying lead may have a stab plate at one or both of its ends to serve as the interface between the umbilical and the structures where the lines, e.g. electrical, optical fiber and/or hydraulic, are terminated.
Stab plates typically are formed with a stainless steel plate and a population of hydraulic and electrical couplers/connectors. A stab plate also may comprise a locking mechanism, a termination bracket for holding the flying lead umbilical, and an ROV bracket. An ROV is employed to deliver the stab plate to a desired subsea location while gripping the ROV bracket. Once at the desired subsea connection location, the ROV is again employed to use a torque tool for connecting the stab plate to a corresponding stab plate, thus forming the subsea stab plate connection.
In many applications, ROVs are used to fly and lock the leads at the desired stab plate connection via an available tool system, such as a tool deployment unit (TDU) or a flying lead orientation tool (FLOT). Each of these types of systems uses a torque tool for locking down one stab plate to a corresponding stab plate, which can result in a complex and time-consuming procedure for forming the subsea connection. Further difficulties may arise in forming a successful subsea connection because existing stab plates can weigh in excess of 100 kg and sometimes in excess of 200 kg without including the weight of the umbilical. Operation of the ROV in performing these complex connection procedures with relatively heavy stab plates creates many difficulties, e.g. large loads acting on the components being connected. As a result, such operations require highly skilled ROV pilots. In some applications, additional difficulties arise from the time required for ROV integration with respect to the corresponding tooling and for calibration of the tools used by the ROV.